Heat recovery systems for machines having an internal combustion engine are known for extracting useful energy from the exhaust stream generated by the internal combustion engine. These systems are used to increase the efficiency of the machine and to minimize energy lost in the form of waste heat. The process involves capturing the waste heat and converting it into a form of mechanical energy. The mechanical energy can then provide power back to the machine.
A variety of systems for converting waste heat into mechanical work have been applied, such as, for example, turbochargers, Rankine cycles, Stirling engines, or the like. However, many of these techniques use only one heat source and provide power directly back to the engine or compressor, requiring complex mechanical linkages and control devices.
International Application Publication WO2010063368 (hereinafter “the '368 publication”), purports to describe a motor vehicle having a waste heat recovery device for using a plurality of waste heat sources of a motor vehicle by converting the useable waste heat into mechanical work and/or electrical energy. According to the '368 publication, a Rankine cycle converts waste heat from the engine into mechanical work, and a current generator or electric motor transforms the mechanical work into electric energy. However, the Rankine cycle of the '368 publication may be expensive, complex, difficult to package within a machine, or combinations thereof.
Thus, an improved heat recovery system for converting waste heat into useable energy is desired to improve the fuel economy and power response of a machine.